US9594449B2 - Electronic device including touch-sensitive display - Google Patents

Abstract

A method includes detecting a touch on a touch-sensitive display, determining a time of a display update of the touch-sensitive display, and adjusting a scanning rate of scanning electrodes of the touch-sensitive display based on the time of the display update.

Description

FIELD OF TECHNOLOGY

The present disclosure relates to electronic devices including, but not limited to, portable electronic devices having touch-sensitive displays and their control.

BACKGROUND

Electronic devices, including portable electronic devices, have gained widespread use and may provide a variety of functions including, for example, telephonic, electronic messaging and other personal information manager (PIM) application functions. Portable electronic devices include several types of devices including mobile stations such as simple cellular telephones, smart telephones (smart phones), Personal Digital Assistants (PDAs), tablet computers, and laptop computers, with wireless network communications or near-field communications connectivity such as Bluetooth® capabilities.

Portable electronic devices such as PDAs, or tablet computers are generally intended for handheld use and ease of portability. Smaller devices are generally desirable for portability. A touch-sensitive display, also known as a touchscreen display, is particularly useful on handheld devices, which are small and may have limited space for user input and output. The information displayed on the display may be modified depending on the functions and operations being performed.

Improvements in electronic devices with touch-sensitive displays are desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a portable electronic device in accordance with the disclosure.

FIG. 2 is a front view of an electronic device in accordance with the disclosure.

FIG. 3 illustrates pulses of current signal utilized to drive a drive electrode during scanning in accordance with the disclosure.

FIG. 4 is a flowchart illustrating an example of a method of detecting touches on a touch-sensitive display in accordance with the disclosure.

FIG. 5 andFIG. 6 are timelines illustrating detection of touches and reporting the touches in relation to the display update.

DETAILED DESCRIPTION

The following describes an electronic device and a method of controlling the electronic device. The method includes detecting a touch on a touch-sensitive display, determining a time of a display update of the touch-sensitive display, and adjusting a length of time of scan of the touch-sensitive display based on the time of the display update. For simplicity and clarity of illustration, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. Numerous details are set forth to provide an understanding of the embodiments described herein. The embodiments may be practiced without these details. In other instances, well-known methods, procedures, and components have not been described in detail to avoid obscuring the embodiments described. The description is not to be considered as limited to the scope of the embodiments described herein.

The disclosure generally relates to an electronic device, which is a portable electronic device in the embodiments described herein. Examples of portable electronic devices include mobile, or handheld, wireless communication devices such as pagers, cellular phones, cellular smart-phones, wireless organizers, PDAs, wirelessly enabled notebook computers, tablet computers, and so forth. The portable electronic device may also be a portable electronic device without wireless communication capabilities, such as a handheld electronic game device, digital photograph album, digital camera, or other device.

A block diagram of an example of a portableelectronic device100 is shown inFIG. 1. The portableelectronic device100 includes multiple components, such as aprocessor102 that controls the overall operation of the portableelectronic device100. Theprocessor102 may be a single processor, a dual-core processor, or multiple processors, although theprocessor102 is referred to in singular form. The portableelectronic device100 presently described optionally includes acommunication subsystem104 and a short-range communications132 module to perform various communication functions, including data and voice communications. Data received by the portableelectronic device100 is decompressed and decrypted by adecoder106. Thecommunication subsystem104 receives messages from and sends messages to awireless network150. Thewireless network150 may be any type of wireless network, including, but not limited to, data wireless networks, voice wireless networks, and networks that support both voice and data communications. Apower source142, such as one or more rechargeable batteries or a port to an external power supply, powers the portableelectronic device100.

Theprocessor102 interacts with other components, such as Random Access Memory (RAM)108,memory110, a touch-sensitive display118, an auxiliary input/output (I/O)subsystem124, adata port126, aspeaker128, amicrophone130, short-range communications132, andother device subsystems134. Input via a graphical user interface is provided via the touch-sensitive display118. The touch-sensitive display118 includes adisplay112 operatively coupled to adisplay controller120 and a touch-sensitive overlay114 operatively coupled to atouch controller116, also referred to as a touch driver. Theprocessor102 interacts with thedisplay112 via thedisplay controller120. Theprocessor102 interacts with the touch-sensitive overlay114 via thetouch controller116. Information, such as text, characters, symbols, images, icons, and other items that may be displayed or rendered on a portable electronic device, is displayed on the touch-sensitive display118 via theprocessor102. Theprocessor102 may interact with anaccelerometer136 that may be utilized to detect direction of gravitational forces or gravity-induced reaction forces, for example, to determine the orientation of theelectronic device100.

To identify a subscriber for network access, theelectronic device100 may optionally use a Subscriber Identity Module or a Removable User Identity Module (SIM/RUIM)card138 for communication with a network, such as thewireless network150. Alternatively, user identification information may be programmed intomemory110.

Theelectronic device100 includes anoperating system146 and software programs orcomponents148 that are executed by theprocessor102 and are typically stored in a persistent, updatable store such as thememory110. Additional applications or programs may be loaded onto theelectronic device100 through thewireless network150, the auxiliary I/O subsystem124, thedata port126, the short-range communications subsystem132, or any othersuitable subsystem134.

A received signal, such as a text message, an e-mail message, or web page download, is processed by thecommunication subsystem104 and input to theprocessor102. Theprocessor102 processes the received signal for output to thedisplay112 and/or to the auxiliary I/O subsystem124. A subscriber may generate data items, for example e-mail messages, which may be transmitted over thewireless network150 through thecommunication subsystem104, for example.

One or more touches, also known as touch contacts or touch events, may be detected by the touch-sensitive display118. Theprocessor102 may determine attributes of the touch, including a location of a touch. Touch location data may include an area of contact or a single point of contact, such as a point at or near a center of the area of contact. A signal is received at thetouch controller116 when a touch is detected. A touch may be detected from any suitable input member, such as a finger, thumb, appendage, or other objects, for example, a stylus, pen, or other pointer. Thetouch controller116 and/or theprocessor102 may detect a touch by any suitable input member on the touch-sensitive display118. Multiple simultaneous touches may be detected.

One or more gestures may also be detected by the touch-sensitive display118. A gesture, such as a swipe, also known as a flick, is a particular type of touch on a touch-sensitive display118 and may begin at an origin point and continue to an end point. A gesture may be identified by attributes of the gesture, including the origin point, the end point, the distance travelled, the duration, the velocity, and the direction, for example. A gesture may be long or short in distance and/or duration. Two points of the gesture may be utilized to determine a direction of the gesture. A gesture may also include a hover. A hover may be a touch at a location that is generally unchanged over a period of time or is associated with the same selection item for a period of time.

Anoptional force sensor122 or force sensors may be disposed in any suitable location, for example, between the touch-sensitive display118 and a back of theelectronic device100 to detect a force imparted by a touch on the touch-sensitive display118. Theforce sensor122 may be a force-sensitive resistor, strain gauge, piezoelectric or piezoresistive device, pressure sensor, or other suitable device. Force as utilized throughout the specification refers to force measurements, estimates, and/or calculations, such as pressure, deformation, stress, strain, force density, force-area relationships, thrust, torque, and other effects that include force or related quantities.

Force information related to a detected touch may be utilized to select information, such as information associated with a location of a touch. For example, a touch that does not meet a force threshold may highlight a selection option, whereas a touch that meets a force threshold may select or input that selection option. Selection options include, for example, displayed or virtual keys of a keyboard; selection boxes or windows, e.g., “cancel,” “delete,” or “unlock”; function buttons, such as play or stop on a music player; and so forth. Different magnitudes of force may be associated with different functions or input. For example, a lesser force may result in panning, and a higher force may result in zooming.

A front view of an example of theelectronic device100 is shown inFIG. 2. Theelectronic device100 includes the touch-sensitive display118. The touch-sensitive display118 may be a capacitive touch-sensitive display that includes capacitive touch sensors. The touch sensors include, for example, drive electrodes, also referred to as scanning electrodes, and sense electrodes. Theelectrodes202 and theelectrodes204 may comprise any suitable material, such as indium tin oxide (ITO). Theelectrodes202 and theelectrodes204 are not visible when viewing theelectronic device100 but are illustrated inFIG. 2 for the purpose of the present description. In the example illustrated inFIG. 2, thevertical electrodes202 may be the drive electrodes and thehorizontal electrodes204 may be the sense electrodes. Alternatively, thehorizontal electrodes204 may be the drive electrodes and thevertical electrodes202 may be the sense electrodes.

In this example, thedrive electrodes202 and thesense electrodes204 are coupled to thetouch controller116, for example, via a flex connector. Thedrive electrodes202 are driven by thetouch controller116 such that pulses of signal are carried by thedrive electrodes202. The signal may be, for example, current or applied voltage. Thesense electrodes204 are utilized to detect changes in the signal at thenodes206, which are the locations at which thesense electrodes204 cross over thedrive electrodes202. To determine a touch location, the touch-sensitive display118 is scanned by driving thedrive electrodes202 while signals from asense electrode204 are received at thetouch controller116. Each scan of the touch-sensitive display118 includes multiple frames. In each frame, adrive electrode202 is driven utilizing multiple pulses, while receiving signals from asense electrode204. Eachdrive electrode204 may be driven in multiple frames while sensing utilizing each of thesense electrodes204.

An example ofmultiple pulses202 of signal utilized to drive adrive electrode202 in one frame of a scan is illustrated inFIG. 3. In the example ofFIG. 3, current pulses are illustrated, and adrive electrode202 is driven utilizing 8 square wave pulses. Alternatively, the pulses may be grouped. For example, a drive electrode may be driven utilizing two groups, each comprising four pulses. The groups are separated by a period of time that may be greater than the period of time between the pulses that comprise a group.

A flowchart illustrating an example of a method of detecting touches on the touch-sensitive display118 is shown inFIG. 4. The method may be carried out by software executed, for example, by thetouch controller116. Coding of software for carrying out such a method is within the scope of a person of ordinary skill in the art given the present description. The method may contain additional or fewer processes than shown and/or described, and may be performed in a different order. Computer-readable code executable by at least one processor of the portable electronic device to perform the method may be stored in a computer-readable medium, such as a non-transitory computer-readable medium.

When a touch is detected402, the next display update time is determined404, and the length of time of a scan, or scan time, is adjusted406 based on the display update time such that the touch data is reported by thetouch controller116 to theprocessor102 in time to update thedisplay112 based on the touch data.

An example of a timeline illustrating detection of a touch and reporting the touch by adjusting the scan time based on the display update time is illustrated inFIG. 5.

In the example ofFIG. 5, a touch is detected at time T504. The touch is detected during a scan of the touch-sensitive display118 and prior to completion of the scan. The signals received from thesense electrodes204 are utilized to detect a touch during the scan, rather than awaiting completion of the scan to detect a touch. For example, driving may be completed for 3 of 12 of thedrive electrodes202, but not completed for the remaining 9 of 12 of thedrive electrodes202. The touch may be detected at thetouch controller116, based on the signals received from thesense electrodes204 during the frames in which the first 3drive electrodes202 are driven.

Thetouch controller116 is operably coupled to thedisplay controller120, and thetouch controller116 receives a signal, referred to as the Vertical Synchronization or Vsync signal, from thedisplay controller120. The Vsync signal is sent from thedisplay controller120 to thetouch controller116 each time thedisplay112 is updated to update the displayed information. Thedisplay112 is updated at regular intervals of time and the Vsync signal is received by thetouch controller116 at regular intervals in time. The regular interval is determined by thetouch controller116 and thetouch controller116 determines the time of the next display update. In the example ofFIG. 5, the display is updated at time T502, prior to detecting the touch at time T504. Based on the regular interval, or display update rate, the time of the next display update is determined to be time T508.

To report the touch data to theprocessor102 in time to utilize the touch data in the next display update at time T508, thetouch controller116 adjusts the scan time to report the touch data to theprocessor102 at time T506, prior to the display update at time T508. Thetouch controller116 determines the time between time T504 and time T508. Thetouch controller116 also determines the number of frames remaining in the scan and determines the length of time remaining for each frame in order to complete the scan by time T506. Based on the calculated frame time and the length of time for each pulse utilized to drive thedrive electrodes202 during scanning, the number of pulses utilized to drive eachdrive electrode202 in each frame is determined. The number of pulses in each frame is decreased to decrease the time of the frame to the calculated frame time. The number of pulses is decreased to complete the scan in the time remaining until time T506. For example, the number of pulses may be decreased from 8 pulses, as illustrated inFIG. 3, to 4 pulses.

Optionally, the touch data may be reported to theprocessor102 along with a confidence bit. Based on the confidence bit, theprocessor102 determines whether or not to utilize the data when updating thedisplay112. For example, thetouch controller116 may determine a confidence bit based on the number of pulses per electrode. In this example, the confidence bit may be 75% when 6 pulses are sent rather than 8. Theprocessor102 may determine whether or not to use the data based on the confidence bit received from thetouch controller116 application or function performed. For example, when scrolling, the data may be utilized when a low confidence bit is reported to theprocessor102 because small inaccuracies may have little effect on the function performed. When drawing on the touch-sensitive display118, however, the accuracy of the data may be more important, and the processor may not utilize data when a low confidence bit is reported. The confidence bit may be reported to the host via a register in the interface. Each bit of the register may correspond to a confidence level, e.g., 10%, 25%, and so forth.

The scan rate may be adjusted by adjusting the number of pulses such that a subsequent scan is completed, and the touch data is reported to thecontroller102 at time T510 prior to the next display update at time T512.

As described above, the pulses may be grouped. In the example in which pulses are grouped, the number of pulses in each group may be reduced. Alternatively, or in addition to reducing the number of pulses in each group, the number of groups may be reduced.

Another example of a timeline illustrating detection of a touch and reporting the touch by adjusting the scan rate based on the display update time is illustrated inFIG. 6.

In the example ofFIG. 6, a touch is detected and the touch data is reported by thetouch controller116 to theprocessor102 at time T604, after the display is updated at time T602. In the example ofFIG. 6, the touch is detected when the full scan of the touch-sensitive display118 is complete.

Thedisplay112 is updated again at time T606. The time between the display update at time T606 and time T608 is determined. Time T608 is the time by which the touch data is reported to utilize the touch data when thedisplay112 is updated at time T610. The adjusted rate of scanning may be maintained during the touch to continue reporting touch data prior to updating thedisplay112.

Optionally, the touch data may be reported to theprocessor102 along with a confidence bit. Based on the confidence bit, theprocessor102 determines whether or not to utilize the data when updating thedisplay112.

When pulses are grouped, the number of pulses in each group may be reduced. Alternatively, or in addition to reducing the number of pulses in each group, the number of groups may be reduced.

By reducing the number of pulses during touch detection, the time utilized to scan the touch-sensitive display118 is decreased. The number of pulses utilized in each frame of a scan is determined based on the time remaining until the next display update such that the touch data from the scan is reported to theprocessor102 in time to utilize the touch data when updating thedisplay112. By adjusting the scan time to report the touch data prior to updating the display, the delay, also referred to as latency, between a touch or touch movement and displaying information relating to the touch or touch movement is reduced. For example, when drawing a line on the touch-sensitive display118, latency causes a delay between the touch and displaying the line such that the displayed line may lag behind the touch. By adjusting the scan rate based on the display update, the lag is reduced.

A method includes detecting a touch on a touch-sensitive display, determining a time of a display update of the touch-sensitive display, and adjusting a length of time of a scan of the touch-sensitive display based on the time of the display update. An electronic device includes a touch sensitive display at at least one controller coupled to the touch-sensitive display and configured to detect a touch on the touch-sensitive display, determine a time of a display update of the touch-sensitive display, and adjust a length of time of a scan of the touch-sensitive display based on the time of the display update.

The present disclosure may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the present disclosure is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims (16)

What is claimed is:

1. A method comprising:

beginning a scan of a touch-sensitive display, the scan including a plurality of frames in which drive electrodes are driven while signals are received from sense electrodes such that a respective drive electrode is driven in each frame while signals are received from the sense electrodes;

in response to detecting a touch during the scan of the touch-sensitive display and prior to completion of the scan:

determining a length of time until a next display update; and

decreasing a time of remaining frames of the scan to complete the scan and report the scan prior to a time of a next display update of the touch-sensitive display,

wherein each first frame of the scan completed prior to detecting the touch is completed in a first length of time and each second frame of the scan completed after detecting the touch is completed in a second length of time that is less than the first length of time.

2. The method according toclaim 1, comprising utilizing a scan rate for a subsequent scan such that the subsequent scan is completed and touch data from the subsequent scan is reported prior to a time of a subsequent display update immediately following the next display update.

3. The method according toclaim 1, wherein decreasing the time of remaining frames of the scan comprises reducing a number of pulses applied to the drive electrodes that are driven in the remaining frames of the scan such that drive electrodes driven prior to detecting the touch are driven by applying a first number of pulses and the drive electrodes that are driven after detecting the touch are driven by a second number of pulses that is less than the first number of pulses.

4. The method according toclaim 1, wherein determining the length of time until the next display update comprises determining a time based on a Vertical Synchronization signal from the touch-sensitive display.

5. The method according toclaim 1, comprising reporting touch data for the scan and a confidence bit to a processor.

6. The method according toclaim 5, wherein the confidence bit is determined based on the number of pulses applied to the electrodes after detecting the touch.

7. The method according toclaim 6, comprising determining whether or not to utilize the touch data based on the confidence bit and based on the function performed utilizing the touch data.

8. A non-transitory computer-readable medium having computer-readable code executable by at least one processor of a portable electronic device to:

begin a scan of a touch-sensitive display, the scan including a plurality of frames in which drive electrodes are driven while signals are received from sense electrodes such that a respective drive electrode is driven in each frame while signals are received from the sense electrodes;

in response to detecting a touch during the scan of the touch-sensitive display and prior to completion of the scan:

determine a length of time until a next display update; and

decrease a time of remaining frames of the scan to complete the scan and report the scan prior to a time of a next display update of the touch-sensitive display,

wherein each first frame of the scan completed prior to detecting the touch is completed in a first length of time and each second frame of the scan completed after detecting the touch is completed in a second length of time that is less than the first length of time.

9. An electronic device comprising:

a touch-sensitive display;

a controller coupled to the touch-sensitive display and configured to:

begin a scan of a touch-sensitive display, the scan including a plurality of frames in which drive electrodes are driven while signals are received from sense electrodes such that a respective drive electrode is driven in each frame while signals are received from the sense electrodes;

in response to detecting a touch during the scan of the touch-sensitive display and prior to completion of the scan:

determine a length of time until a next display update; and

decrease a time of remaining frames of the scan to complete the scan and report the scan prior to a time of a next display update of the touch-sensitive display,

wherein each first frame of the scan completed prior to detecting the touch is completed in a first length of time and each second frame of the scan completed after detecting the touch is completed in a second length of time that is less than the first length of time.

10. The electronic device according toclaim 9, wherein the controller is configured to utilize a scan rate for a subsequent scan such that the subsequent scan is completed and touch data from the subsequent scan is reported prior to a time of a subsequent display update immediately following the next display update.

11. The electronic device according toclaim 9, wherein the controller is configured to decrease the time of remaining frames of the scan by reducing a number of pulses applied to the drive electrodes that are driven in the remaining frames of the scan such that the drive electrodes driven prior to detecting the touch are driven by applying a first number of pulses and the drive electrodes that are driven after detecting the touch are driven by a second number of pulses that is less than the first number of pulses.

12. The electronic device according toclaim 9, wherein the controller is configured to report touch data for the scan and a confidence bit to a processor.

13. The electronic device according toclaim 12, wherein the controller is configured to determine the confidence bit based on the number of pulses applied to the electrodes after detecting the touch.

14. The electronic device according toclaim 13, comprising a processor coupled to the controller, wherein the processor is configured to determine whether or not to utilize the touch data based on the confidence bit and based on a function performed utilizing the touch data.

15. The electronic device according toclaim 9, wherein the controller comprises a touch controller, and a display controller is coupled to the touch controller to send a Vertical Synchronization signal from the display controller to the touch controller.

16. The electronic device according toclaim 15, wherein the touch controller is configured to determine the length of time until the next display update by determining a time based on the Vertical Synchronization signal from the display controller.

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